Mercury switch



June 7, 1938. R, R MATTER 2,119,944

MERCURY SWITCH Filed Feb. 21, 195e' Patented June 7, 1938 UNITED STATES MERCURY SWITCH Raymond P. Mattern,

Minneapolis, Minn., as-

- signor to Minneapolis-Honeywell Regulator Company, Minneapolis, Minn., a corporation of Delaware Application February 21, 1936, Serial No. 65,095

13 Claims.

This invention relates to mercury switches and more particularly to that type of switch wherein there is a delayed action in the opening or closing of a circuit through the switch.

One object of this invention is the provision of an improved switching mechanism wherein there is an appreciable predetermined interval between movement of the switch to closed circuit position and the closing of the circuit thereby.

10 Another object is the provision in a mercury switch of improved means to insure an eiiicient making and breaking of the circuit therethrough and the substantial preclusion of arcing.

f A further object is the provision of improved 15 mechanism associated with a switch whereby the time interval may be varied in individual switches by the inclusion of a single element in the assembly, the conflguration of which element may be suitably varied to provide a differential in the 20 time lag.

A further object is the provision of improved means to permit the ow of mercury in one direction substantially instantaneously and retard the flow thereof in another direction for anY ap- 25 preciableinterval.

A further object is the provision of a mechanism which will be unusually reliable and dependable in operation and of suilicient durability and strength to withstand all normal shocks incident 30 to usage, installation and transportation thereof.

Other objects will in part be obvious and in part pointed out hereinafter.

The invention, accordingly, consistsof the arrangements of parts, combinations of elements 35 and features of construction all as will be more fully described hereinafter and disclosed in the accompanying drawing, and the scope of the application of which will be indicated in the appended claims.

Referring now to the drawing:

Figure 1 is a side sectional elevation showing the mechanism of the improved switch tilted to one of its positions of adjustment;

Figure 2 is a sectional view taken. along the 45 line 2-2 of Figure 1 as viewed from the right;

` Figure 3 is an isometric view of certain portions of the mechanism of the switch, and

Figures 4, 5, and 6 aire isometric views 'of various forms of one of the elements comprising a 50 part of the instant invention, certain features thereof being shown in dotted lines; y

. Similar reference characters refer to similar parts throughoutthe several views of the drawing.'

Referring now to Figure 1, there is generally indicated at I an envelope or tube which is prefcrablycf glass and may beof a suitable hard glass, such as G-'l02EJ, containing a body of mercury, generally indicated at II. Contained with- 60 in tube Ill and suitably secured thereto in any de- (Cl. 20o-33) sired manner, as by fusing or cementing, is a septum or partition I2 which has a passageway I3 extending therethrough. Passage I3 may be enlarged adjacent one face of septum I2 to provide a space I4, in order to reduce the volume of the material utilized. As better shown in Figure 3, a second passageway I5 extends completely through septum I2 adjacent the upper extremity thereof. Suitable apertures I6 having enlarged lower extremities I1 are preformed in septum I2 in order to accommodate a suitable gate member I8, rotatable about apivot I9 and having an inclined edge surface 20 adapted to abut, when in closed position, the interior periphery of tube I0.

Septum I2 may be constructed of any suitable arc-resisting material although that ceramic substance known in the art as lava is preferably utilized. Gate I8 may be constructed oi. any suitable heat resisting material although in the preferred embodiment a. suitable metal, such as chromium steel, has been found preferable. These materials are used in order that, should it be desirable to fuse septum I2 to tube I0, the pivotal operation of gate I8 whichl is assembled prior to sealing of tube Ill by the passing of pivot I9 through enlarged portion I1 and the body of gate I8 through apertures I6 in such manner that gate I8 is in substantial alignment with passage I5 and free for rotation about pivot I9 therein, is not impaired. Extending rearwardly from passage I5 is a sloping surfacel 2I which has positioned adjacent a lower extremity thereof a rearwardly extending portion 22 which has mounted thereon, as by means of a suitable cement 23, a'

cup 24. Cup 24 is constructed of an arc-resisting material, such as porcelain, and has an inclined upper surface or rim 25 for a purpose to be more fully described hereinafter.'

A suitable well 26 is formed in the wall of tube I0 below and adjacent cup 25. An electrode 21 extends through the wall of Well 26 and is suitably sealed therein. A second electrode 28 extends downwardly through the upper wall of tube I0, to which it is sealed, im@ cup 24 to a position adjacent the bottom thereof. A laterally extending contact member 29 is positioned adjacent the lower extremity of electrode 28 and suitably secured thereto, as by welding, to insure a reliable contact. any suitable hard glass, such as G-'l02EJ or G-702P is positionedabout andv vcircumferential with electrode 28 and extends below the lowermost inclination of inclined rim 25 of cup 24. Electrode 28 may be pinched, as at 3|, to hold sleeve 30 in its desired position, or, if desired, sleeve 30 may be fused directly to electrode 28. Positioned in passageway I3 and frictionally held in engagement with the walls thereof, is an insertable member 32 having a restricted passageway 33 through its v'longitudinal bore.

A glass sleeve 30 of yto mately atmospheric pressure.

Member 32 may also be of any desired arc-resisting material but in the preferred embodiment of the invention unred lava has been found desirable, as this material permits a relatively free flow of mercury.

As better shown in Figure 3, an indentation 34 is provided in the front wall 35 of sep-tum l2 adjacent gate I8 in order to provide access of mercury il to the lower portion of gate i8 when in its open position. Tube Ill may be suitably sealed as at 36.

As better shown in Figure 1, when the switch is tilted to a circuit closing position, the weight of the body of mercury Il engages, through indentation 34, the lower portion of gate I8, which is of a density to oat on mercury, and rotates the same about pivot I9 to a closed position to preclude the flow of mercury through passage I5. Gate I8 being closed, mercury iiows through passages i3 and 33 into well 26 and gradually lls that end of tube I adjacent well 26 until it reaches the rim 25 of cup 24 which it overflows to establish electrical contact between electrodes 21 and 28.

It may here be noted that a gas is preferably contained in the tube and may comprise a volume of hydrogen or other suitable gas at approxi- As the mercury ows through passages I3 and 33, the gas in that end of tube lll is compressed until its pressure is suilicient to open gate I 8 a very slight amount against the pressure of mercury Ii, at which time a quantity of gas passes into the other end of the tube and the weight of the mercury again becomes sufficient to close gate itl. This cycle is repeated intermittently until the mercury has ceased to flow and the gas pressure at opposite ends of the tube has equalized. If desired, however, a clearance may be provided between the walls of passage I5 and gate i8 sufficient to permit passage of gas but insuflicient to allow flow of mercury.

It should also be noted that a small volume of mercury is contained at all times in cup 24 and well 26 in order that the circuit break may be occasioned by the separation of the two bodies of mercury, rather than of mercury and a solid electrode, which serves to allow for higher current carrying capacities and longer life.

The inclination of rim 25 is preferably such that when the switch is tilted to its normal circuit closing position, rim 25 will be substantially horizontal in order that mercury may ow into cup 24 from all directions substantially simultaneously to insure a satisfactory and virtually instantaneous contact. In the absence of such inclination, it will be seen that mercury would rst enter cup 24 adjacent the rear thereof and its passage possibly be retarded by the restricted space between sleeve 30 and the rear wall of cup 24 to permit a vacillating or otherwise uncertain contact which would be manifestly undesirable. It may here be pointed out that sleeve 3l! prevents contacting of the mercury with electrode 28 at its upper extremity or above rim 25 of cup 24.

Upon tilting of the switch to circuit breaking position, mercury I I flows up incline 2l into passage I5 and by its weight forces gate I8 to rotate to open position, as indicated by dotted lines iii Figure l, and iiows rapidly through the large cpening so provided into the opposite end of the tube. The amount of mercury above rim 25 of cup 24 is normally relatively small and will ow substantially instantaneously through passage iii to break the contact between electrodes 21 and 28.

It will readily be seen that the time required to close the circuit may be varied by the inclination of the switch, the mercury flowing more rapidly under the increased pressure of the bulk thereof as the angle of inclination approaches the vertical. In certain installations, however, it is undesirable to vary the angle of inclination and in such cases other means for varying the time lag must be provided in order to accommodate the various requirements. Such an adjustment may be provided by varying the dimensions of aperture 33 which passes through member `32, and it will be understood that the time lag for a given angle of inclination may be readily computed with respect to any given diameter of aperture 33.

In mass production of the device, however, it would be exceedingly costly and impractical to manufacture an individual switch for each requirement with regard to the period of time lag. Accordingly, members 32 may be made of substantially the same exterior diameter but having different sizes of passageways 33 therethrough, as shown in Figures 4.-, 5, and 6. The diameter of passageways 33 may be mathematically determined and these elements manufactured in a variety of sizes, each size adapted to provide a certain period of time lag at a given inclination and inserted in various otherwise identical switches, as desired in accordance with the peculiar requirements of the individual installation.

From the foregoing it will be seen that there is herein provided an improved mercury Switch which accomplishes the objects of the invention in an improved manner including many practical advantages.

As many possible embodiments may be made of the instant invention and as many changes may be made in the embodiment above set forth, it is intended that ail matter hereinbefore set forth or disclosed in the drawing shall be interpreted as illustrative and not in a limiting sense.

I claim as my invention:

l. A switching mechanism, comprising, in combination, a tube, electrodes sealed in said tube, mercury in said tube adapted to bridge said electrodes, a septum in said tube in the path of ow of said mercury, a pivotedgate member positioned in a passageway in said septum adjacent the upper portion thereof and adapted to abut the inner periphery of the uppermost portion of said tube whereby to permit the ow of mercury in one direction and restrict the flow thereof from the opposite direction, the arrangement being such that said gate is adapted to float upon said mercury and be closed by the flow thereof in one direction upon tilting of said tube and adapted to be depressed and opened by said mercury upon iiow thereof in the opposite direction, and a passageway through the lower portion of said septum to permit the flow of said mercury in said one direction.

2. A switching mechanism, comprising, in combination. a tube. electrodes sealed in said tube, mercury in said tube adapted to bridge said electrodes, a septum in said tube in the path of flow of said mercury, a cup carried by said septum, said cup having an inclined peripheral edge, the axis of inclination thereof being substantially equal touthe axis of inclination of said tube when tilted to circuit closing position whereby said edge assumes a substantially horizontal plane hen said switch is in said circuitclosing position.

3. A switching mechanism, comprising, in combination, a tube, electrodes sealed in said tube, mercury in said tube adapted to bridge said f electrodes, a septum in said tube in the path of flow of said mercury, a cup carried by said septum, said cup having an inclined peripheral edge, the axis of inclination thereof being substantially equal to the axis of inclination of said tube when tilted to circuit closing position whereby said edge assumes a substantially horizontal plane when said switch is in said circuit closing position, an extremity of one of said electrodes extending into said cup, means to permit the flow of mercury in one direction and restrict the now thereof in the opposite direction and a passageway to permit a relatively slow ow of mercury in said opposite direction.

4. A switching mechanism, comprising, in combination, a tube, electrodes in said tube, mercury adapted to bridge said electrodes, a ceramic septum in said tube and fused thereto positioned in the path of flow of said mercury, a passageway in said septum, a gate positioned therein, said gate permitting the now of mercury in one direction and precluding the ow in the other direction and a by-pass about said gate to permit the ow of said mercury in said other direction.

5. A switch comprising, in combination, a tube, electrodes in said tube, mercury in said tube for bridging said electrodes, a septum in said tube positioned in the path of ow of said mercury, said septum having an elongated passage, a plurality of members each having a restricted opening of different size and adapted to be frictionally held in said passage.

6. A switching mechanism comprising, in combination, a tube, electrodes in said tube, mercury in said tube for bridging said electrodes, a septum in said tube positioned in the path of flow of said mercury, said septum having an elongated passageway, a plurality of interchangeable members each one having therethrough a bore of different diameter and adapted to be mounted and frictionally retained in said passageway.

'7. A switching mechanism comprising, in combination, a tube, electrodes in said tube, mercury in said tube for bridging said electrodes, a ceramic septum positioned in said tube in the path of flow of said mercury, an aperture in said septum, a gate pivoted in said aperture, an elongated passageway through said septum, a member having a restricted opening therethrough in said passageway.

8. A switching mechanism, comprising, in combination, a tube, electrodes in said tube, mercury in said tube adapted to bridge said electrodes, a septum positioned in said tube in the path of flow of said mercury, a cup supported by said septum, a passageway in said septum above said cup, a second restricted passageway in said septum below said cup, the arrangement being such that said mercury passes through said second restricted passageway to gradually overflow the lip of said cup upon tilting of said switch in one direction and iiows through said first passageway upon tilting of said switch in the opposite direction, and means to close said first mentioned passageway upon tilting of said tube in one direction and open said passageway upon tilting of said tube in the opposite direction.

9.' A switching mechanism, comprising, in combination, a tube, electrodes sealed in said tube, mercury in said tube adapted to bridge said electrodes, an arc-resisting septum positioned in said tube in the path of ow of said mercury, a passageway in said septum, pivoted means in said passageway to permit the flow of mercury in one direction and preclude the flow thereof in the other direction, a second passageway through said septum to permit the flow of said mercury in said other direction and means to vary the diameter of said second passageway whereby the time required for said mercury to flow therethrough may be varied..

l0. A switching mechanism, comprising, in combination, a tube, electrodes sealed in said tube, mercury in said tube adapted to bridge said electrodes, an arc-resisting septum positioned in said tube in the path of ilow of said mercury, a passageway in said septum, pivoted means in said passageway to permit the flow of mercury in one direction and preclude the ow thereof in the other direction, a second passageway through said septum to permit the now of said mercury in said other direction, means to vary the diameter of said second passageway `whereby the time required for said mercury to flow therethrough may be varied, a cup carried by said septum, the arrangement being such that one of said electrodes extends into said cup and said mercury flowing through said second passageway overflows the rim thereof to bridge said electrodes, said cup having an inclined rim, the axis of inclination thereof being substantially equal to the axis of inclination of said switch when tilted to its open position whereby upon such tilting said rim is substantially horizontal to permit an equally diffused flow of mercury thereover from all directions simultaneously.

11. A switching mechanism, comprising, in combination, a tube, electrodes in said tube, mercury in said tube adapted t'o bridge said electrodes, a ceramic septum positioned in said tube in the path of flow of said mercury, an aperture in said septum, a gate pivoted in said aperture to permit the ow of mercury in one direction and preclude its ow in the other direction, a passageway through said septum and interchangeable means to 'vary the internal diameter of said passageway, said interchangeable means comprising a plurality oi insertable members adapted to be positioned in said passageway, said last mentioned members having bores of different diameter passed axially therethrough.

12. A switch comprising in combination, a tube, electrodes in said tube, an electrical conducting fluid in said tube for bridging said electrodes, a septum in said tube positioned in the path of flow of said fluid and having a passageway therethrough, and a member having a restricted opening of predetermined size in said passageway.

13. A switching mechanism comprising, in combination, a. tube, electrodes in said tube, mercury in said tube for bridging said electrodes, a ceramic septum in said tube in the path of ow of said mercury, a passageway through said septum, a member having an orificeof predetermined size mounted in said passageway for controlling the flow of mercury through said passageway.

RAYMOND P. MATTERN. 

